The invention relates generally to fueling of compressed gas tanks, and more particularly, to methods and apparatus for controlling fueling of compressed gas tanks.
Typically, the driver fuels the vehicle at a filling station. Hydrogen vehicles have a defined infrared communication protocol between the refueling station and the vehicle. It is a unidirectional communication (vehicle to refuel station) based on an infrared signal (SAE J 2601, SAE J 2799). Infrared (IR) LEDs and the RDI controller which communicate with a vehicle controller are mounted next to the receptacle. Additional LEDs for showing information concerning the state of the refueling process can also be installed.
FIG. 1 is an illustration of a standard communication interface between a vehicle 10 and a refueling station 15. The vehicle engine control unit (ECU) 20 has an electrical connection 25 to the RDI-controller 30, which is mounted next to the receptacle where the refueling nozzle is connected, typically towards the back of the vehicle. The wiring harness for the electrical connection 25 has four to five single wires, for example, for the power supply, a ground, an enable pin, communication, and the like. The number of wires will vary depending on the specific system being used. The RDI-controller 30 has an electrical connection 35 to the optical frontend 40, which is mounted around the receptacle. IR-LEDs 45 and visible state LEDs 50 are located in the optical frontend 40. The visible LEDs 50 show the driver the state of the refuel/vehicle. The electrical connection 35 has four single wires, for example. The signal from the IR-LEDs 45 is received by the refuel nozzle 55, which is part of the refueling station 15
The optical frontend, which includes the IR-LEDs and the state LEDs, has low reliability. High temperature variation and high temperature gradients next to the receptacle result in high thermal stress for the diodes. Condensation can occur, leading to corrosion and reducing contact resistance. In addition, the mechanical stress caused by thermal expansion can shear off the diode contacts. Furthermore, the stand-alone RDI controllers need a CAN node, increasing the bus traffic which is undesirable.